Couette type reactor apparatus consists of two cylinders mounted one inside the other for rotation relative to one another about a common axis, the cylinders providing a narrow annular processing gap between their opposed stator inner and rotor outer surfaces. The materials to be processed are fed into an annular space formed therefrom.
Such apparatus is described and shown, for example, in U.S. Pat. Ser. No. 5,279,463 (issued 18 Jan., 1994); U.S. Pat. No. 5,538,191 (issued 23 Jul. 1996), and U.S. Pat. No. 6,471,392 (issued 29 Oct., 2002), the disclosures of which are incorporated herein by reference. In another type of the apparatus described in these disclosures describe cylindrical rotor and stator that have their longitudinal axes parallel but displaced from one another to provide an annular flow passage that varies in radial dimension about the circumferences of the opposed surfaces.
Such apparatus is operable, for example, to quickly chemically react two or more materials together with high reaction rates In general, most chemical reactions are to a greater or lesser degree either endothermic or exothermic, and many are very strongly so. The achievement of the highest possible heat transfer rate, if possible higher than is strictly necessary in order to provide a margin for adjustment, is therefore desirable to ensure that the processing temperature can at all times readily be maintained within those required limits, which can constitute a very narrow range, e.g. ±1° C.
The requirement to transfer or exchange heat energy between bodies, and/or between fluids separated by a body wall, and/or between a body and a fluid, is essential in a vast number of processes and apparatus. Heat exchanger apparatus design and application is now a very mature art. Such apparatus may consist of a separate structure to which the transfer fluid is supplied and from which it is discharged, or it may be associated with and/or form part of apparatus in which the heat energy is produced or consumed. When employing liquid heat transfer fluids, temperatures will rise when cooling a surface and will drop when heating a surface. There are however many special cases, especially in chemical reaction processes, when surfaces which contain and control the reactants, are required to remove or introduce heat to the reactants very rapidly and at an as constant as possible temperature in order to avoid the production of unwanted side products or to improve reaction yields. Due to the fact that the heating or cooling liquids usually flow along the surfaces to be heated or cooled, picking up or giving up heat along their path, it is very difficult to obtain high heat flux rates through such surfaces and simultaneously maintain uniform and constant temperatures with such applications. There is therefore a constant endeavor to develop heat exchange methods which enable high heat flux rates while simultaneously maintaining uniform and constant temperatures on surfaces such as those used in chemical processing.